Iron Golf Club Head

ABSTRACT

An iron golf club head of a cavity type, specifically called a pocket type head, manufactured by forging to have a lowered center of gravity, capable of giving an excellent ball hitting sensation in hitting a golf ball. This iron golf club head is integrally provided by forging and includes a top  2  in an upper portion of the head, a face  3  at a front, a sole at a bottom, a back  5  at a rear. A main recess  7  is formed to extend toward the face  3  in the back  5 , and a concavity  8  is formed by a bending process, to extend from the main recess  7  to the sole  4.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an iron golf club head manufactured by forging.

2. Description of the Related Art

Iron golf club heads generally fall into a muscle type and a cavity type according to the shape of their rear surface. Cavity type heads include an undercut type and a pocket type.

Muscle type iron heads, also called blade type or flat-back type, are conventional ones with comparatively flat rear surfaces. Muscle type iron heads have the advantage of excellent ball hitting feeling being given when hitting a golf ball at a so-called sweet spot. Muscle type iron heads, however, are so shaped that general golfers have difficulties in using the same due to comparatively higher center of gravity and smaller moment of inertia thereof.

On the other hand, cavity type heads are of an iron type and have hit the streets relatively recently, having a shape with a cavity on a rear surface thereof. Cavity type iron heads, although they give somewhat inferior ball hitting feeling compared with muscle type heads, have advantageous features that a sweet spot is wider and a shake of head is smaller when a golf ball fails to be hit by the sweet spot due to its larger moment of inertia since a head weight reduced by forming the cavity on the rear surface is distributed to a periphery thereof.

Of the cavity type heads, so-called undercut type heads are ones in which a recess or concavity is extended from a main recess toward a sole on a rear surface thereof. Further, so-called pocket type heads, which are relatively new type iron heads that have recently hit the streets, have a pocket-shaped recess defined by enlarging the above-mentioned undercut type recess farther toward a sole, such that the recess enlarged toward the sole is shaped as if it were a pocket. According to the iron heads of these types, a head weight reduced by forming the recess enlarged toward the sole can be freely distributed, thus improving, e.g., a degree of freedom in designing a center of gravity such as in lowering the center of gravity. This enables a golf club to be easily used by general golfers.

And now, when manufacturing the iron heads of these undercut and pocket types by forging, it is a general method to join a face and a main body, which are separately manufactured in advance, to each other by welding (see, e.g., Japanese unexamined patent application publication No. 2006-223686). It is, however, difficult to allow their joint surfaces to be fully joined to each other by welding, and therefore there remains an extremely slight gap on the joint surfaces where the face and the main body are left unjoined, although it is only a very small part. Hence, there has been a drawback that a inferior ball hitting feeling is resulted in hitting a golf ball.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide an iron golf club head of a cavity type, specifically, a pocket type thereof manufactured by forging so as to have a lowered center of gravity, and give an excellent ball hitting feeling in hitting a golf ball.

A first aspect of the present invention is an iron head golf club having a top at a top of the head, a face at front thereof, a sole at a bottom thereof, and a back at a rear thereof, including:

a main recess formed in the back so as to extend toward the face; and

a concavity formed to extend from the main recess to the sole, the concavity being formed by a bending process.

A second aspect of the present invention is the iron head golf club in which in the head of the first aspect, the concavity is formed without undergoing any of a cutting process and a joining process.

A third aspect of the present invention is the iron head golf club in which in the head of the first or second aspect, fiber flows are allowed to be present continuously from the top to the face, the sole and the back.

According to the iron golf club head of the first aspect of the present invention, the main recess and the concavity are provided and hence its center of gravity can be lowered. Further, the concavity is formed by a bending process and hence the excellent ball hitting feeling is given to a user in hitting a golf ball.

According to the iron golf club head of the second aspect in the present invention, the concavity is formed without undergoing any of the cutting process and the joining process. Hence, the iron golf club head can be manufactured at low cost.

According to the iron golf club head of the third aspect of the present invention, the fiber flows are allowed to be present continuously from the top to the face, the sole and the back. Hence, high strength of the iron golf club head is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention will become more apparent upon reading of the following detailed description and the accompanying drawings in which:

FIG. 1 is a rear view of an iron golf head club according to a first embodiment of the invention, illustrating a rear portion thereof viewed from a direction perpendicular to a face surface thereof.

FIG. 2 is a top plan view thereof, illustrating a top portion thereof viewed from a direction parallel to the face surface thereof.

FIG. 3 is a cross-section al view thereof taken on an A-A line in FIG. 1 according to the first embodiment.

FIG. 4 is a rear view thereof, illustrating the rear portion thereof viewed from the direction perpendicular to the face surface prior to performing a bending process.

FIG. 5 is a top plan view thereof, illustrating the top portion thereof viewed from the direction parallel to the face surface prior to performing the bending process.

FIG. 6 is a cross-sectional view thereof taken on an A-A line in FIG. 4 according to the first embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next is a description of preferred embodiments of an iron golf club head of the present invention with reference to the accompanying drawings.

In FIG. 1 to FIG. 3 showing an iron golf club head of a first embodiment of the present invention, numeral symbol 1 denotes an iron golf club head (hereunder, referred to as “head”) formed in a one-piece structure by forging. The head 1 includes a top 2 in an upper portion thereof, a face 3 at a front thereof, a sole 4 at a bottom thereof, and a back 5 at a rear thereof. The head 1 also includes a hosel on one side for a shaft to be inserted thereinto. The top 2 defines a top surface 21 acting as an upper surface of the head 1. The face 3 defines a face surface 31 acting as a front surface of the head 1. Likewise, the sole 4 defines a sole surface 41 acting as a bottom surface thereof, and the back 5 defines a back surface 51 acting as a rear surface thereof.

The back 5 is formed with a main recess 7 extending toward the face 3. The main recess 7 is formed in such a concave shape that it is concaved toward a front from the back surface 51 to the face 3. The main recess 7 is also referred to as a “cavity”, due to its cavity shape. Further, a concavity 8 is formed to extend from the main recess 7 to the sole 4. The concavity 8 is formed in such a concave shape that it is extended toward a bottom from the main recess 7 to the sole 4, and is encompassed with a lower potion of the face 3, the sole 4, and the back 5. In addition, the concavity 8 is pocket-shaped and therefore is referred to as a pocket as well.

The concavity 8 is formed by a bending process, which is described in detail hereunder.

FIG. 4 to FIG. 6 show a head 1 a prior to allowing the same to undergo a bending process. The head 1 is shaped by forging, using, e.g., S20C as a material. It is to be noted herein that in FIG. 4 to FIG. 6, the same numeric symbols are used for the same parts as those in FIG. 1 to FIG. 3

An extending portion 9 is provided in such a manner as to extend from the sole 4 toward a rear side. The extending portion 9 has a comparatively thin tongue shape. A junction between the extending portion 9 and the sole 4 is formed with a groove 10 for making a bending process easy. Further, a cutout 11 is formed at each of two positions in the back 5. The cutout 11 is formed beforehand in order to prevent the extending portion 9 and the back 5 from interfering with each other in folding the extending portion 9.

At the time of the bending process, the extending portion 9 is bent at a substantially right angle in the groove 10 using a press machine so that a front edge of the extending portion 9 faces the top 2. As a result, the back surface 51 as well as the pocket-shaped concavity 8 is formed by the extending portion 9. Thus, without undergoing any of a cutting process and a joining process, the concavity 8 is formed through the bending process only. Accordingly, fiber flows are allowed to be present continuously from the top 2 to the face 3, the sole 4 and the back 5.

Note that in the present invention, any manufacturing processes other than the bending process are the same as those applied to conventional ordinary iron golf club heads, and therefore the description thereof is omitted.

Next, ball hitting sounds of the head 1 actually manufactured according to the present embodiment were analyzed in order to evaluate the ball hitting feeling given in hitting a golf ball. In this analysis, the frequency components of the sound emitted at the time of hitting a golf ball were measured to determine a component whose acoustic pressure was the highest. For comparison, conventional muscle type, cavity type and pocket type heads were evaluated in a similar fashion. Together with the evaluation, the height of the center of gravity for each head was measured. The result is shown below.

In this evaluation test, tested sample heads include a conventional muscle type head that has a comparatively rear flat surface, a cavity type head provided with a concavity on a rear surface thereof that is, however, not of an undercut shape, and a pocket type head provided with a pocket-shaped concavity formed so as to extend from a main recess to a sole on a rear surface thereof. Note that the pocket type heads shown as the comparative examples are the ones in which their face and main body were joined by welding.

TABLE 1 Ball Hitting Height of Center of Type Welding Sound(Hz) Gravity(mm) Present Pocket NA 3,771 18.3 Embodiment Comparative Muscle NA 3,926 19.5 Example 1 Comparative Muscle NA 3,916 Example 2 Comparative cavity NA 4,240 18.9 Example 3 Comparative cavity NA 4,298 Example 4 Comparative pocket applied 3,300 18.6 Example 5 Comparative pocket applied 3,047 Example 6

From the result, it was confirmed that the ball hitting feeling or sensation given by the head 1 of the present embodiment was so close to those of the comparative muscle type heads that it was excellent enough. Further, the height of the center of gravity of the head 1 of the present embodiment was so close to those of the comparative pocket type heads that it was low enough.

As described above, the iron golf club head of the present embodiment is formed in one-piece structure by forging, including the top 2 in the upper portion, the face 3 at the front, the sole 4 at the bottom, the back 5 at the rear, and the main recess 7 formed to extend toward the face 3 in the back 5, and the concavity 8 formed to extend from the main recess 7 to the sole 4, in which the concavity 8 is formed by a bending process. Due to the main recess 7 and the concavity 8 being formed, the center of gravity of the head can be lowered, and due to the concavity 8 being formed by a bending process, the iron golf club head of the present embodiment is capable of giving an excellent ball hitting feeling or sensation in hitting a golf ball.

It should be noted that the concavity 8 can be formed without undergoing any of the cutting process and the joining process, thus enabling the head 1 to be manufactured at low cost.

Also, since the fiber flows are allowed to be present continuously from the top 2 to the face 3, the sole 4 and the back 5, high strength of the head 1 is ensured.

In addition, the present invention is not limited to the foregoing embodiment and various modifications are possible. For example, the cutouts 11 may be infilled by performing a welding process after the bending process. 

What is claimed is:
 1. An iron golf club head having a top at a top of the head, a face at front thereof, a sole at a bottom thereof, and a back at a rear thereof, comprising: a main recess formed in the back so as to extend toward the face; and a concavity formed to extend from the main recess to the sole, said concavity being formed by a bending process.
 2. The iron golf club head according to claim 1, wherein said concavity is formed without undergoing any of a cutting process and a joining process.
 3. The iron golf club head according to claim 1, wherein fiber flows are allowed to be present continuously from the top up to the face, the sole and the back.
 4. The iron golf club head according to claim 2, wherein fiber flows are allowed to be present continuously from the top up to the face, the sole and the back. 